crazy scroll bar

My scroll bar seems to jump up and down no matter what program I am using, word,Internet,excel, etc…. I am running Win xp and I uninstalled the service pack just to back track still doesn't slow it up any. I have ran lots of different checkers to look for adware,trojans,bugs etc… but no seem to find anything.. Any suggestions on how to find the source of this problem. The tater

Tater, I posted to your HijackThis log. Go here:
http://forums.tomcoyote.org/index.php?showtopic=35465&hl=